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Biomedical subjects

D Waite

Publications and source records attributed to D Waite.

At least 19 recordsLinked to original sources
PubMed2001

Materials selection for a dry atmospheric mercury deposits sampler.

In order to develop a sampler for measuring dry deposition rates for atmospheric mercury, suitable materials are needed that neither adsorb nor release mercury. In this paper, four materials (polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS), Teflon and glass) were tested. Each of the materials was placed in a beaker containing mercuric solution under varied conditions for pH, preservative concentration, initial mercuric concentration, temperature, acid type and contact time of the material. The concentrations of the mercuric solutions were determined using the cold-vapor atomic absorption (CVAA) technique. The experimental results show that glass has the lowest absolute net adsorption rates (NARs) of 0.026-1.13 pg/m2 among the materials tested. Teflon, PVC and ABS have NARs ranging from 0.54 to 10.4 microg/M2 over an adsorption duration of one or two weeks. ABS has significantly higher adsorption rates for mercury than PVC and Teflon, indicating its inappropriateness as the material for building the sampler. Teflon and PVC will be the materials of choice for the sampler. The experimental results can also be used in establishing appropriate sampling conditions in the field.

Acrylic Resins↗
PubMed1999

Interaction with amylopectin influences the ability of granule-bound starch synthase I to elongate malto-oligosaccharides.

This paper examines the properties in soluble form of two isoforms of starch synthase. One of these, granule-bound starch synthase I (GBSSI), is responsible for the synthesis of amylose inside the amylopectin matrix of the starch granule in vivo. The other, starch synthase II (SSII), is involved in amylopectin synthesis. Both isoforms can use amylopectin and malto-oligosaccharide as substrates in vitro. As well as acting as a substrate for GBSSI, amylopectin acts as an effector of this isoform, increasing the rate at which it elongates malto-oligosaccharides and promoting a processive rather than distributive mode of elongation of these compounds. The affinity of GBSSI for amylopectin as an effector is greater than its affinity for amylopectin as a substrate. The rate and mode of elongation of malto-oligosaccharides by SSII are not influenced by amylopectin. These results suggest that specific interaction with amylopectin in the matrix of the starch granule is a unique property of GBSSI and is critical in determining the nature of its products.

Amylopectin↗
PubMed1999

Granule-bound starch synthase I in isolated starch granules elongates malto-oligosaccharides processively.

Isoforms of starch synthase belonging to the granule-bound starch synthase I (GBSSI) class synthesize the amylose component of starch in plants. Other granule-bound isoforms of starch synthase, such as starch synthase II (SSII), are unable to synthesize amylose. The kinetic properties of GBSSI and SSII that are responsible for these functional differences have been investigated using starch granules from embryos of wild-type peas and rug5 and lam mutant peas, which contain, respectively, both GBSSI and SSII, GBSSI but not SSII and SSII but not GBSSI. We show that GBSSI in isolated granules elongates malto-oligosaccharides processively, adding more than one glucose molecule for each enzyme-glucan encounter. Granule-bound SSII can elongate malto-oligosaccharides, but has a lower affinity for these than GBSSI and does not elongate processively. As a result of these properties GBSSI synthesizes longer malto-oligosaccharides than SSII. The significance of these results with respect to the roles of GBSSI and SSII in vivo is discussed.

Adenosine Diphosphate Glucose↗
PubMed1999

Incarcerated adolescents' distress and suicidality in relation to parental bonding styles.

This study examines the relationships between the bonding style of an incarcerated adolescent with parents and his/her current feelings of self-esteem, hopelessness, and suicidal thoughts and attempts. It also investigates differences between bonding to mother and bonding to father. Some 296 incarcerated adolescents were interviewed using the Parental Bonding Instrument. Significant relationships were found between youths' self-esteem, hoplessness, and suicidal behavior and their bonding style. Youths whose parent(s) had a parental bonding style of affectionless control reported the greatest distress, and youths whose parent(s) had an optimal bonding style reported the least distress. Differences were found between bonding styles with the mother and with the father. Attachment theory may be useful in targeting incarcerated youths who have affectionless control bonding with parent(s) for special interventions since these youths are most at risk for psychosocial problems.

Adolescent↗
PubMed1999

Specificity of starch synthase isoforms from potato.

In higher plants several isoforms of starch synthase contribute to the extension of glucan chains in the synthesis of starch. Different isoforms are responsible for the synthesis of essentially linear amylose chains and branched, amylopectin chains. The activity of granule-bound starch synthase I from potato has been compared with that of starch synthase II from potato following expression of both isoforms in Escherichia coli. Significant differences in their activities are apparent which may be important in determining their specificities in vivo. These differences include affinities for ADPglucose and glucan substrates, activation by amylopectin, response to citrate, thermosensitivity and the processivity of glucan chain extension. To define regions of the isoforms determining these characteristic traits, chimeric proteins have been produced by expression in E. coli. These experiments reveal that the C-terminal region of granule-bound starch synthase I confers most of the specific properties of this isoform, except its processive elongation of glucan chains. This region of granule-bound starch synthase I is distinct from the C-terminal region of other starch synthases. The specific properties it confers may be important in defining the specificity of granule-bound starch synthase I in producing amylose in vivo.

Amino Acid Sequence↗
PubMed1999

Adolescent inhalant abuse: environments of use.

A questionnaire survey of 285 consecutively recruited adolescents who were adjudicated to juvenile correctional facilities in Virginia was conducted using the Inhalant Use Questionnaire (1). White youths (36.1%) and youths from other ethnic backgrounds (44.4%) are significantly more likely to report past inhalant use than black youths (1.4%). The median age reported for first-time use of inhalants is 13 years. Youths were divided between those who experimented with inhalants (27%) and those who were heavy users (27%). Huffing was preferred by 60% of youths. Of the youths, 52% reported using inhalants with friends present, whereas 34% used inhalants when they were alone. Sites where youths reported inhalant use include at a friend's home (68%), at home (54%), on the street (40%), at parties (28%), on school grounds (26%), and at school (18%). There are no gender differences in age of onset of inhalant use, lifetime frequency of inhalant use, frequency of inhalant use in the past year, or preferred method of using inhalants. The five substances most frequently used as inhalants include gasoline (by 57.4%), Freon (40.45%), butane lighter fluid (38.3%), glue (29.8%), and nitrous oxide (23.4%). There were no gender differences for use of other products.

Adhesives↗
PubMed1997

Hantavirus pulmonary syndrome: CD8+ and CD4+ cytotoxic T lymphocytes to epitopes on Sin Nombre virus nucleocapsid protein isolated during acute illness.

In 1993 a number of cases of unexplained adult respiratory syndrome occurred in the southwestern United States. The illness was characterized by a prodrome of fever, myalgia, and other symptoms followed by the rapid onset of a capillary leak syndrome with hemoconcentration, thrombocytopenia, and pulmonary edema. Viral RNA sequences in the lungs identified a new member of the hantavirus genus, Sin Nombre virus (SNV), unique to North America. Pulmonary endothelial cells were heavily infected but were not necrotic. We speculated that this capillary leak syndrome was initiated by immune responses to the SNV-infected pulmonary endothelial cells. We isolated a CD8+ cytotoxic T lymphocyte (CTL) clone directly from the blood of a patient with the acute hantavirus pulmonary syndrome (HPS) which recognizes a SNV specific epitope on the virus nucleocapsid protein (aa 234-242) that is restricted by HLA C7 and produces IFN gamma but not IL-4. We identified a second CD8+ CTL epitope located within another site aa 131-139 on the nucleocapsid protein, which is HLA B35 restricted, and a CD4+ CTL epitope located on a third site on nucleocapsid protein aa 372-380 using lymphocytes obtained during HPS from another patient that were stimulated in vitro. Hantavirus specific CD8+ and CD4+ CTL may contribute to the immunopathology and capillary leak syndrome observed in the HPS.

Acute Disease↗
PubMed1995

Prevalence of HIV-related risk behaviors and STDs among incarcerated adolescents.

PURPOSE: To determine the HIV-related risk behaviors and STDs in a population of incarcerated adolescents in order to strategically target education and prevention efforts. METHODS: A single point-in-time prevalence study based on an analysis of intake medical records of 1,215 incarcerated youth were analyzed for HIV risk behaviors and STD history. RESULTS: Incarcerated adolescents report high rates of risk behaviors for HIV infection and STDs, with 75% reporting three or more sex partners, 25% never using condoms and 19% having a current diagnosis of at least one STD. Significantly more females than males reported a history of STDs and had higher rates of current diagnoses of chlamydia/non-gonococcal urethritis, trichomonas and gonorrhea. CONCLUSIONS: Ethnic/racial and gender differences were found in risk behaviors for STDs among a sample of incarcerated adolescents.

Adolescent↗
PubMed1994

Loss of RT6 message and most circulating T cells after thymectomy of diabetes prone BB rats.

T cells expressing the RT6 surface alloantigen perform important immunoregulatory functions in the rat. Diabetes prone (DP) BB rats are deficient in circulating RT6+ T cells and develop spontaneous autoimmune diabetes mellitus. Transfusions leading to engraftment of RT6+ T cells prevent the disease. Coisogenic diabetes resistant (DR) BB rats do circulate RT6+ T cells and are free of disease. We investigated the basis for the deficiency of RT6+ T cells in the DP-BB rat and made the following observations. 1. Thymectomy causes the rapid loss of most peripheral T cells in the DP-BB rat. 2. Concomitant with the loss of T cells is the total loss of mRNA encoding RT6. 3. In contrast to the effects observed in peripheral lymphoid tissues, thymectomy does not lead to a detectable loss in RT6+ protein found in the small intestine. We conclude that the deficiency of RT6+ peripheral T cells in the DP-BB rat is due either to their short life span or to their reduced proliferative capacity following release from the thymus.

ADP Ribose Transferases↗
PubMed1994

Results of the ACSUS for pediatric AIDS patients: utilization of services, functional status, and social severity.

OBJECTIVE: This study describes demographic characteristics of pediatric AIDS patients, describes hospital and community-based service utilization patterns, and analyzes medical and social support service usage patterns with respect to patient demographic characteristics, clinical trial participation, functional/developmental status, and social environment. DATA SOURCES AND STUDY SETTING: Data reported in this study are from the AIDS Costs and Service Utilization Survey (ACSUS) and cover the six-month period beginning March 1991 (N = 135). Pediatric patients who sought care for HIV-related problems were sampled at seven different hospitals in five metropolitan regions of the United States. All of the participating hospitals had clinics specifically serving pediatric patients infected with HIV. The sample consists of HIV-positive patients who had had at least one HIV-related symptom or condition. STUDY DESIGN: A stratified probability sample design guided the sampling strategy, which included oversampling in two large hospitals from two of the five metropolitan areas. Survey data cover an 18-month time period of health care utilization, cost, and financing information from HIV-infected patients and their providers. Utilization measures are standardized to a six-month period. Per capita income, family structure, informal personal network, functional status, and clinical trial participation are tested for associations with patterns of utilization. In addition, a weighted ten-point social severity scale was developed to assess family/household stability. DATA COLLECTION: Data were collected through a screener instrument completed by the person accompanying the child to a hospital clinic visit (usually a a parent), and through two interviews conducted in person with the patients' primary caregivers. Data from the questionnaires were coded and assembled into computerized SAS analysis files by WESTAT: PRINCIPAL FINDINGS: Children in this sample are 62 percent African American, 25 percent Hispanic, and 10 percent White. Medicaid is the primary payer for 92 percent. Mean per capita income is $3,440. Fewer than one-half (41 percent) of the families of the children receive Aid to Families with Dependent Children (AFDC). (AFDC). Within the six-month period, approximately one-third of the sample (29.6 percent) was hospitalized. Mean length of stay was 16.0 days. Clinical trial participation was positively related to mean number of hospital clinic visits and receipt of formal (paid) home care. There were no differences in use of community clinic, mental health, and inpatient facilities by clinical trial status. Participation in clinical trials was positively related to income and negatively related to social severity. In four cities, emergency room use was consistently lower for clinical trial participants than for nonparticipants. CONCLUSIONS: Data from the first six months of the ACSUS pediatric sample suggest that participation in clinical trials may bring about access to social services that appear to reduce emergency room use. However, the findings reported here are descriptive and exploratory. Further multivariate, nonparametric analyses of the full 18-month provider-patient merged data set are necessary to confirm the simple correlations found in this study.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Treatment of 171 patients with pulmonary tuberculosis resistant to isoniazid and rifampin.

BACKGROUND AND METHODS: The frequency of infection with multidrug-resistant Mycobacterium tuberculosis is increasing. We reviewed the clinical courses of 171 patients with pulmonary disease due to M. tuberculosis resistant to rifampin and isoniazid who were referred to our hospital between 1973 and 1983. The patients' records were analyzed retrospectively. Their regimens were selected individually and preferably included three medications that they had not been given previously and to which the strain was fully susceptible. RESULTS: The 171 patients (median age, 46 years) had previously received a median of six drugs and shed bacilli that were resistant to a median of six drugs. Thus, their regimens were frequently not optimal. Of 134 patients with sufficient follow-up data, 87 (65 percent) responded to chemotherapy (as indicated by negative sputum cultures for at least three consecutive months); 47 patients (35 percent) had no response, as shown by continually positive cultures. The median stay in the hospital was more than seven months. In a multivariate analysis, an unfavorable response was significantly associated with a greater number of drugs received before the current course of therapy (odds ratio, 4.0; 95 percent confidence interval, 1.6 to 9.9; P < 0.001) and with male sex (odds ratio, 2.5; 95 percent confidence interval, 1.1 to 6.2; P < 0.03). Twelve of the patients with responses subsequently had relapses. The overall response rate was 56 percent over a mean period of 51 months. Of the 171 patients, 63 (37 percent) died, and 37 of these deaths were attributed to tuberculosis. CONCLUSIONS: For patients with pulmonary tuberculosis that is resistant to rifampin and isoniazid, even the best available treatment is often unsuccessful. Only about half of such patients eventually have negative sputum cultures despite carefully selected regimens administered for extended periods. Failure to control this resistant infection is associated with high mortality and ominous implications for the public health.

Adolescent↗
PubMed1986

Alveolar ridge maintenance with hydroxylapatite ceramic cones in humans.

The efficacy of solid cones of hydroxylapatite ceramic implanted in fresh extraction sockets for the preservation of alveolar bone was evaluated. Ten experimental subjects (70 implants) and eight control subjects (63 extractions) were treated. After extraction, hydroxylapatite ceramic cones were inserted into the sockets at least 1 mm below the alveolar crest in the experimental group. Alveolar ridge resorption was measured on lateral cephalometric radiographs, and statistical analysis was performed. The follow-up periods ranged from 12 to 24 months (mean, 20.6 months). Thirty-seven of the 70 hydroxylapatite ceramic cone implants (53%) became exposed, and 19 cones (27%) had to be removed. It was concluded that hydroxylapatite ceramic cone implants placed in fresh extraction sockets do not significantly preserve alveolar bone.

Adult↗
PubMed1986

Chondromyxoid fibroma.

A brief review of the literature concerning chondromyxoid fibroma is presented. 7 previous cases and the present case of the tumor in the jaws are described. Parallels to the extra oral lesions are drawn and in the light of previously published data, distinctive diagnostic features are discussed. The importance of close cooperation between the surgeon, the radiologist and the pathologist is stressed to avoid a misdiagnosis and radical treatment of the malignant counterpart of a rare benign tumor.

Adult↗
PubMed1984

Alveolar bone graft resorption associated with abnormal dental follicle.

An unusual case of an alveolar bone graft that underwent almost complete resorption in association with a large radiolucent lesion around the erupting canine is reported. Clinical and radiographic follow-up after grafting is important to detect and manage any pathologic changes which might occur. Early detection of any abnormal radiologic changes and surgical intervention to excise the lesion could prevent further destruction of the grafted bone.

Alveolar Process↗
PubMed1980

Abnormal cilia in Polynesians with bronchiectasis.

Bronchial or nasal ciliated epithelium from 13 patients with bronchiectasis (12 Polynesians and 1 European) was examined by electron microscopy. All cilia examined lacked dynein arams. In 2 patients, this was the only abnormality observed, but in the others, various ciliary abnormalities were present, including cilia with missing tubules, extra tubules, and misplaced tubules, as well as compound cilia, intracytoplasmic cilia, vesiculated cilia, and cilia with long winglike folds. In all of these patients pulmonary mucociliary transport rates were either absent or markedly reduced. It is suggested that these abnormalities were due to a mutation or group of mutations, which was the underlying cause of the bronchiectasis.

Adult↗
PubMed1979

A simplified method of monitoring muco-ciliary transport.

A radioactive powder, formed by drying 99Tcm sulphide colloid, was used as a tracer to determine both lung clearance and tracheal mucosal transport of inhaled particles simultaneously in normal and bronchiectatic subjects. No change in either parameter with posture was noted in normal subjects, but patients with bronchiectasis exhibited rapid lung clearance when supine and slow clearance when erect, demonstrating the inefficient muco-ciliary transport in these patients. The method seems of value in monitoring the progress of bronchiectatic patients.

Bronchiectasis↗